1 You are familiar with the metamorphosis of butterflies, the cycle that begins with an egg and goes through caterpillar to chrysalis to butterfly. You know that butterflies are metamorphic, but did you know that rocks are metamorphic as well? It's true!
2 We covered igneous and sedimentary rocks in Part 1. They are related to the third type of rock. When certain processes are applied to igneous or sedimentary rocks, they become metamorphic rocks, the third type of rock found on Earth.
3 Metamorphism occurs within the Earth's crust rather than on the surface. Most metamorphism takes place from 6 to 19 miles below the Earth's surface. That means we don't see metamorphic rock nearly as often as the igneous (from lava or magma) or sedimentary (layers of pressed sediment) types of rocks.
